The proposed studies involve examination of normal and cataract lens tissues. An unexplored area of lens molecular biology and biochemistry will be studied, namely post-transcriptional modification of lens messenger RNA (mRNA) molecules. The studies will use molecular biological and biochemical techniques to focus on two areas of interest: (a) to discern the structure of messenger RNA molecules which code for specific lens proteins and (b) to identify, isolate and characterize the enzymes associated with specific structural features in the mRNA examined. Correlations between changes in the modification enzyme system and mRNA structures in differentiating cells at various stages of lens development , growth and aging will be made, normal lenses will be examined first, followed by examination of cataractous lenses. Cell culture methods will be employed.